Single-Seater Baby B-17

By Stephan Wilkinson
5/4/2012 • Aviation History, Aviation History Briefing

“This is the most challenging thing I’ve ever done,” Bally admits. “I bit off two mouthfuls when I started this project.”

While there are plenty of 7/8-scale and even 3/4-scale flying fighter replicas—the latter would give an F4U Corsair look-alike a wingspan of just under 30 feet—nobody has ever tried to shrink a four-engine bomber down by two-thirds and still make it flyable. Nobody but Jack Bally, of Dixon, Ill., that is. Bally is building a 1/3-scale Boeing B-17 replica that will be about the size of a Cessna 152, and it’s well on its way to completion. “I’m about 90 percent done, with 90 percent to go,” says Bally, obviously a wise old aircraft homebuilder. He has in fact built three other sportplanes already, though not nearly of his current project’s complexity. “This is the most challenging thing I’ve ever done,” he admits. “I bit off two mouthfuls when I started this project.”

Bally began with a detailed set of plans for a 1/9-size radio-controlled model B-17, scaled them up, and loosely based his all-metal airframe on the model’s wooden components. The pilot’s seat, instrument panel and controls fill the entire B-17 cockpit and are fully enclosed by the multi-paned canopy and cockpit roof, now a single piece hinged at one side for entry. The airplane will remain a single-seater at least for awhile, though Bally is considering putting a tandem passenger seat directly behind the pilot’s.

The faux B-17 is a remarkably accurate replica externally, and Bally can think of few compromises he’s had to make. “The gear-retraction mechanism is hydraulic and not through jackscrews, and the engines aren’t radials,” he points out. “They’re Hirth F30s, four cylinders opposed, 2-stroke, detuned from 80 hp each to about 60 because I’ll run them direct-drive.” (In order to put out the full 80 hp, the engines would have to turn so fast that a gearbox would be needed to keep prop speeds reasonable, but a total of 240 hp should be plenty for an airplane this size.)

Bally hasn’t logged the time he’s spent on his baby B-17, but he calculates that 40 hours of work on it every week for 12 years comes to just under 25,000 hours. Does he know when it will finally fly? “Oh, hell no. I once thought it should have been five years ago; now it’s still probably two or three years in the future.”

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